Flush Denormal Results to Zero

Contraction of FP Multiply and Add/Subtract Operations

-IPF_fma[-] enables [disables] the contraction
of floating-point multiply and add/subtract operations into a single operation.
Unless -mp is specified, the compiler contracts
these operations whenever possible. The -mp option
disables the contractions. Use -IPF_fma and -IPF_fma- to override the default compiler behavior.
For example, a combination of -mp and -IPF_fma
enables the compiler to contract operations (on Itanium®-based
systems only):

prompt>icpc
-mp -IPF_fma prog.cpp

FP Speculation

-IPF_fp_speculationmode
sets the
compiler to speculate on floating-point operations in one of the following
modes:

fast: sets the compiler to
speculate on floating-point operations

safe: enables the compiler
to speculate on floating-point operations only when it is safe

strict: disables the speculation
of floating-point operations.

off: disables the speculation
on floating-point operations.

Note

-IPF_fp_speculationsafe is the default when -O0 is specified.

FP Operations Evaluation

-IPF_flt_eval_method0 directs the compiler to
evaluate the expressions involving floating-point operands in the precision
indicated by the variable types declared in the program.

-IPF_fltacc[-] enables [disables] optimizations
that affect floating-point accuracy. By default (-IPF_fltacc-)
the compiler may apply optimizations that reduce floating-point accuracy.
You may use -IPF_fltacc or -mp
to improve floating-point accuracy, but at the cost of disabling some
optimizations.

-IPF_fp_relaxed[-] enables [disables] use of
faster but slightly less accurate code sequences for math functions, such
as divide and square root. As compared to strict IEEE* precision, using
this option slightly reduces the accuracy of floating-point calculations
performed by these functions, usually limited to the least significant
digit.